JPH06205799A - Filter inserting in blood vessel system - Google Patents

Abstract

PURPOSE: To obtain elasticity, stiffness and axial stability by providing the filter with a plural number of conically expanding elastic digital parts, making the conical circumferential opening part parallel to the wall of a cylinder and binding up two adjacent digital parts with a hair pin shaped wire at the end of the sliding part. CONSTITUTION: Digital parts 2 are conically expanded from the top 3 so that the opening of the cone is kept open 4. Free end of respective digital part is to serve as sliding part 5. That is, the sliding part 5 is put in a direction to the closing part of the cone forming a filter from the end 2a of the digital part coming parallel to the wall of a cylinder 6 parallel to the axis 7 of the cone. The digital parts are to form the sliding part through binding up two adjacent digital parts with a hair pin shaped wire 8 pair by pair; consequently, forming a shape like a clip 10. The filter would include at least six digital parts composed of three wire parts 8 bending like a pin 9.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a filter that is placed in the vasculature, particularly in a vein, to trap blood clots.

[0002]

2. Description of the Prior Art Filters of this type are described, for example, in U.S. Pat. No. 4,688,553. In general, such filters are in the form of small frustoconical cages, which are installed inside the veins of the path to be filtered.
This is generally a vein leading to the heart. It is therefore possible to hold back the blood clot that forms before it enters the heart, in particular to avoid the risk of causing embolism.

Generally, there are two main types of such filters. The first type is a filter obtained by combining wires by welding or winding. Such filters are small and flexible. Once bent, it fits well into a passage that is said to be bulky and difficult to insert and anatomically abnormally curved.

Further, although a filter formed of a plate-shaped member can be mentioned, it is generally manufactured by cutting a part of the filter portion and shaping it. Such a filter has a large bearing surface in contact with the veins, which reduces damage and eliminates the risk of perforation.

However, these two types of filters have various drawbacks. For filters made of wire, the flexibility of the wire causes two major defects. First of all, because of its flexibility, the support force exerted on the wall of the vein is not constant, so that the filter does not fix well and moves. Second, this wire is small. There is a limited support surface for contact with veins, which can lead to damage and perforation. Furthermore, there is a risk of the wires becoming entangled, especially at the moment of installing the device, which reduces the filtration capacity of the filter.

The filter formed from the plate-like member is very stiff in its mounting position and difficult to fit through the first winding path. This filter is relatively large and its surface can spread crevice damage if very sophisticated insertion devices are not available. Furthermore, filters formed from conical sections with filtering members are generally difficult to put in place. Generally, this type of filter is pushed and inserted by a tube called a catheter having a diameter smaller than that of the blood vessel passing through the blood vessel in order to be introduced into the blood vessel. When the filter reaches the end of the insertion tube, it is spread into the blood vessel and its fingers, which may have formed hooks, are spread out and locked in place.

In practice, this type of "spreading" is very difficult to control and, in fact, in the case of basket type filters, the filter axis is placed in a position other than the most preferred position, substantially parallel to the axis of the blood vessel. There are quite a few.

[0008]

SUMMARY OF THE INVENTION The purpose of the present invention is to provide some flexibility for ease of placement, a firm fixation in the vein, and a certain rigidity to ensure high quality filtration performance. And to overcome these drawbacks by proposing a filter with axial stability.

[0009]

SUMMARY OF THE INVENTION The present invention has a plurality of resilient fingers extending from the head in a generally conical shape, each finger having a normal position of use. Is formed in a direction substantially parallel to the cylindrical wall formed by the line delineating the perimeter of the conical opening and the line parallel to the axis of the conical to determine the center of the filter. It has a free end that is a sliding part that supports
The finger-like part comprises a flexible wire together with the gliding part, and a wire which is bent like a hairpin, in which two adjacent finger-like parts are connected at respective ends forming the gliding part. It is characterized in that it is grouped into one group by the above, and they are bent at the peripheral portion of the conical opening of the finger-shaped portion and connected to the sliding portion.

The large support area of the filter when placed in a vein reduces damage due to the contact pressure exerted on the wall of the vein. In addition, the gliding part that determines the center of the filter and supports the filter is firmly fixed from the beginning against the wall of the vein, and the filter is forced into position such that its axis substantially coincides with the axis of the vein. Get burned. This special wire structure allows the fingers and their sliding parts to be deformed in different directions, the fingers are grouped into a narrow space and easy to set up with a good insertion device. Furthermore, by combining the finger-shaped portions one by one, they are not entangled.

According to one characteristic of a preferred embodiment of the present invention, the hairpin-shaped bent wire is folded back in a substantially conical head direction. According to still another feature of the present invention, the finger-shaped portions, in which two adjacent finger-shaped portions are combined, are formed by bending one wire into a clip shape and locally fixing the wire to the head. . According to a variant of the invention, the wire part bent in the shape of a hairpin has a substantially triangular shape. The special shape or "triangulation" of this wire facilitates the simultaneous movement of the two ends of each wire. In the folded position, the filter occupies a small space, but since both ends of the wire extend substantially adjacent to each other, the bundle retains its flexibility even when bundles of wires are gathered and the filter is venous. It does not get entangled even if it is opened inside.

According to yet another feature of the invention, the flexible wire forming the finger portion is generally pointed arched at the end opposite the end joined to the gliding portion and pre-drilled. It is fixed to the open hard head. The present invention preferably further comprises means for attaching the filter to the vein, and more precisely a locking clasp.

[0013]

The present invention will now be described in detail with reference to the accompanying drawings, which are provided merely as non-limiting examples. Referring first to FIG. 1, for example ten fingers 2 emerge from the head 3 and are spread out in a substantially conical shape. The conical opening is not fixed and is in the expanded state indicated by the dotted line 4. The free end of each finger portion is bent to almost the position of the head 3 to form a sliding portion 5 which determines and supports the center. That is, this sliding part 5 is directed from the end 2a of the finger-like part towards the closed side of the cone forming the filter. To be more precise, if the filter 1 is moved so as to draw the line 4, the conical shaft 7 is formed.
If the cylinder obtained by the generation line parallel to is labeled 6, the gliding portion 5 is substantially parallel to the wall of the cylinder 6.

In the present invention, the finger portion of the filter comprises a flexible wire. Especially for metal wires eg AFNOR K 13C20 N16 Fe known under the registered trademark "Phynox"
A suitable grade of stainless steel such as 15 is used. The diameter of the wire ranges from 2/10 mm to 4/10 mm, for example 3/10 mm or 3.5 / 10 mm.

In such a finger-shaped portion, two adjacent finger-shaped portions are grouped into a group by wire portions bent like a hairpin to form the sliding portion. As a result, the fingers are approximately clip 1 as shown in FIG.
Take the form of 0. The filter is bent like a pin 3
Advantageously, it has at least six fingers made of two wire parts, which are arranged at angular intervals such that the filter is axially stable.

Although the filter of the present invention is placed in a conventional manner, it is easily placed due to the flexibility of the filter. FIG. 2 shows the filter 1 that is embedded inside the blood vessel 11 and is embedded so that a blood clot circulating in the blood vessel can be caught on the way. The direction of blood flow is arrow 1
Indicated by 2. The gliding part 5 is firmly fixed to the inner wall of the vein, so that the filter can be located in the center of the blood vessel.

FIG. 3 shows a detailed view of a clip 10 in which two adjacent finger portions 2 are connected by a wire portion bent into a hairpin 9. Advantageously, this pin-shaped wire portion delimits a substantially triangular region 9a, which results in increased stability of the embedded filter.

4 and 5 show a state in which the end portion of the wire is joined to the position of the head 3. According to FIG. 4, the end of the wire 13 forming the finger-like part opposite to the end joined as the gliding part is fixed to the hard head. The ends of the wires are inserted into the same number of holes 15 pre-drilled in the head. The substantially leading arched rigid head 16 has a cylindrical hole 17 at its proximal end. The wire is attached to the head by a cylindrical member 18. The member 18 has a recess 19 whose diameter and height are substantially equal to the diameter and height of the hole and which are parallel to the axis of rotation 20 of the hole and open into the outer surface. These depressions 19 are provided at an angle and the wire placed therein is then fixed by the inner wall 21 of the head as shown in FIG.

The so-called final filter, which is inserted when there is a constant risk of blood clots passing through and remains inserted for the life of the patient, is provided with attachment means so that it does not move in the blood vessel. The filter according to the invention is equipped for this type with attachment means that slightly dig into the wall of the blood vessel. In fact, at least some of the slides of the filter are equipped with locking catches.

The structure and manufacturing method of these fixing clasps will now be described with reference to FIGS. The starting point is, for example, a thin metallic plate, the intermediate material of the catch 22 being cut out to be substantially T-shaped as shown in FIG. The intermediate material thus formed is subjected to a forming operation as shown in FIG. First, the tapered portion is separated from the plane of the intermediate material to form a substantially V shape. The T-shaped cross bar 24 likewise folds and shapes its two arms 24a until they are substantially parallel. Next, the tapered portion 23 has a tip 25 at its end.
Sharpen to form.

The placement of the catch on the wire arm will now be described with reference to FIGS. 8 and 9 show a first method of fixing the clasp to the wire. Figure 8
As shown in Fig. 6, a catch 22 attached to the wire 8
The arm 24a of the crossbar 24 is flattened and fixed at a point 26 around the wire. The arms 24a remain free and parallel, as shown in FIG. 9, which is a cross-sectional view of FIG.

FIGS. 10 and 11 are a second possible method of fixing the clasp. According to FIG. 10, the stopper 22
Is placed on the wire 8 and then the two arms 24a are bent around said wire. FIG. 11 is a sectional view of FIG. 10 showing a state where the arms 24a are bent and their ends are in close contact with each other.

12, 13, 14 show a schematic representation of a method of inserting a filter according to the invention into a blood vessel. The filter is placed through an insertion tube 27, commonly known in the art as a desilet. 12
At 1, the filter 1 is pushed into the tube 27 by means of the pushing means 28. The filter in the folded state is arranged so that the head part 3 comes out last, and the tube 27 is introduced so as to face the blood flow indicated by the arrow 29.

In FIG. 13, the filter 1 is about to exit the tube but is already substantially conical.
FIG. 14 shows the filter 1 after a moment of FIG. The filter is completely unfolded and the gliding part 5 is the axis 3 of the blood vessel.
Has a substantially cylindrical contour that is almost coaxial with 0,
A filter bears weight against the wall of the blood vessel to ensure its position in the center of the vein. Next, the tube 27
Is pulled out through the approach route.

The arrangement method described above corresponds to the attachment of the filter by the jugular vein route. When installed via the femoral route, the filter is in the vein in the opposite direction,
That is, the head is released first, and again the triangular fingers forming the filter ensure that the filter is centered.

Although the present invention has been described above by way of example, it is not limited thereto, and any useful modification can be made without departing from the scope thereof as defined by the following claims. Is clear. Therefore, with the modification of the present invention, the filter described so far can be used as a completely temporary filter. In this case, the filter is not fitted with a fixing clasp. With yet another modification, the clips are all formed by appropriately shaping a single flexible wire,
Substantially fixed at the head.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an open state of a filter of the present invention.

FIG. 2 is a schematic illustration of a filter embedded within a blood vessel.

FIG. 3 is a detailed view of two adjacent fingers joined together.

FIG. 4 shows a wire fixed to a head. The left third of the figure is a sectional view.

5 shows a bottom view about the arrow V in FIG.

FIG. 6 shows two successive steps of forming a clasp.

FIG. 7 shows two successive steps of forming a clasp.

FIG. 8 shows how the bottom of the clasp is flattened around the wire to secure the clasp to the wire.

9 shows a sectional view of the fixing of the clasp substantially on arrow B. FIG.

FIG. 10 shows a modification of the fixing of the clasp in which the clasp base is bent and fixed around the wire.

FIG. 11 shows a cross-sectional view of an arrow C for changing the fixing of the stopper plate.

FIG. 12 shows a step of placing a filter according to the present invention in a blood vessel.

FIG. 13 shows a step of placing a filter according to the present invention in a blood vessel.

FIG. 14 shows a step of placing a filter according to the present invention in a blood vessel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Filter 2 ... Finger part 3 ... Head part 4 ... Dotted line showing an opening 5 ... Sliding part 7 ... Conical shaft 8 ... Flexible wire 9 ... Hairpin 10 ... Clip

Claims (1)

[Claims] 1. A filter, which is placed in the vasculature to catch blood clots, having a plurality of resilient fingers that are spread out from the head in a generally conical shape, each finger being: Formed in a direction substantially parallel to a cylindrical wall formed by a line describing the perimeter of the conical opening and a line parallel to the axis of the conical when each finger is in its normal use position. A free end, which is a sliding part for determining the center of the filter and supporting the filter, and wherein the finger-like part comprises a flexible wire together with the sliding part and two adjacent fingers. The parts are grouped together in one set by a wire that is joined at each end forming the gliding part and bent like a hairpin, and they are bent around the conical opening of the fingers. And connecting to the gliding part A filter characterized by being present.